This invention relates to an apparatus for gathering a fiber web, discharged by a web delivering device of a card, into a sliver, including the step of passing the fiber web through an opening in a fiber web guide element and introducing the gathered fiber web into a trumpet.
According to a known method, the gathered fiber web is introduced from the opening in the fiber web guide element directly into the trumpet and leaves the trumpet as a sliver. Upon increasing the delivery speed of the card, for example, to a web speed of 300 m/min., operational disturbances are experienced due to an air backflow at the trumpet. Further, immediately upstream of the trumpet (as viewed in the direction of fiber travel) the fiber web takes up a significantly greater space than the compressed sliver. The environmental air is entrained by the fiber web into the trumpet; the entrained air quantities increase with increasing speed. The air streaming rearwardly from the trumpet, particularly from its constriction, eventually reaches such a high backflow speed that the incoming fiber web is destroyed or is blown back in several zones. If the fiber web is compressed from a large cross section in the trumpet, the backflow velocities were found to be excessively high in case of web speeds above 100 m/min.